Spawns a floating brain familiar that can be fired towards enemies as a projectile.
Bob's Brain is fired directly from where Isaac is standing.
Bob's Brain is fired directly from where it is located in the chain of familiars behind Isaac, making aiming it slightly more difficult.
If it hits an enemy, it deals 3.5 damage and explodes, further damaging and poisoning monsters.
The explosion deals 60 damage. The poison deals double Isaac's Damage over time.
The explosion deals 100 damage. The poison damage is dealt 4 times, inflicting Isaac's Damage per tick.
The explosion ignores armor.
The explosion can hurt Isaac, dealing a full heart of damage.
This can make picking up the item a risky choice, as Bob's Brain will always fire, regardless of whether or not Isaac will be caught in the explosion.
Once it explodes, it takes a few seconds to re-appear.
This item belongs to the Bob set. Collecting three items from this set will transform Isaac into Bob.
Notes
Bob's Brain is affected by most bomb modifiers.
Bob's Brain only explodes when hitting an enemy, and does not explode upon hitting a fire, poop, or wall. It can destroy poops and fires like normal shots, however.
Bob's Brain never launches immediately upon entering a room unless a tear-firing key is released and pressed again, or until several seconds have passed.
If Isaac has multiple copies of Bob's Brain, only one familiar will be active at a given time, with another one firing immediately after the first has exploded or starts to return from a miss.
Multiple copies of Bob's Brain will float in the same spot in the familiar line.
Each copy takes up their spot on the familiar line, but only the first one launches out. Respawning brains may end up stacking on top of each other.
Familiars that follow behind Isaac have a certain priority in how close their position is to him over other familiars, with Bob's Brain having 5th / 7th priority.
Synergies
BFFS!: The impact damage is increased to 7 and the explosion deals an additional 25 damage.
Mr. Mega: The explosion deals an additional 85/ 50 damage.
Spiders do not spawn, however the explosion leaves behind a puddle of slowing creep.
Bomber Boy: No cross explosions. Damage from the explosion is halved against the initial target, but others caught in the blast take full damage.
Explodes in a cross-shaped pattern. Damage from the main explosion deals a flat 37.5 damage, and any additional explosion deals flat 75 damage to which Bomber boy's damage reduction is not applied.
Bomber Boy + BFFS!: Explosion damages are increased to 1.25x, which are 46.875/93.75 each.
Bomber Boy + Mr. Mega: Explosion damages are increased to 1.5x, which are 56.25/112.5 each.
Bomber Boy + BFFS! + Mr. Mega: Explosion damages are increased to 1.75x, which are 65.625/131.25 each.
Duct Tape: Bob's Brain stays in place relative to Isaac until it is fired.
E. Coli / Flush!: Bob's Brain will explode upon hitting an enemy that has been turned into poop.
Bob's Brain no longer explodes upon hitting poops made from enemies.
Bob's Brain is fired directly from where Isaac is standing.
Bob's Brain is fired directly from where it is located in the chain of familiars behind Isaac, making aiming it slightly more difficult.
The explosion deals 60 damage. The poison deals double Isaac's Damage over time.
The explosion deals 100 damage. The poison damage is dealt 4 times, inflicting Isaac's Damage per tick.
Bob set. Collecting three items from this set will transform Isaac into Bob.
5th / 
7th priority.
BFFS!: The impact damage is increased to 7 and the explosion deals an additional 25 damage.
Mr. Mega: The explosion deals an additional 
Bobby-Bomb
Bob's Curse
Fast Bombs
Ghost Bombs
Rocket in a Jar
Scatter Bombs
Sticky Bombs
Bomber Boy: No cross explosions. Damage from the explosion is halved against the initial target, but others caught in the blast take full damage.
Duct Tape: Bob's Brain stays in place relative to Isaac until it is fired.
E. Coli / 
Flush!: Bob's Brain will explode upon hitting an enemy that has been turned into poop.
